Model parameter estimation for a rate- or distortion-quantization model function

A more accurate model parameter estimation is achieved by using a Kalman filter for discretely estimating the model parameters between the consecutive frames of the frame sequence and performing the correction step of the time-discrete Kalman filter twice per frame, namely first using a measurement value which depends on a complexity measure of the current frame so as to obtain a primarily corrected state of the time-discrete Kalman filter, and secondly using a measurement value which depends on an actual coding rate or distortion of the video encoder in encoding the current frame using a predetermined quantization which, in turn, may have been determined by use of an estimation of the actual rate- or distortion-quantization function according to the primarily corrected state,. A rate-quantization model function is provided which relates the quantization of the video encoder to the coding rate of the video encoder and is piecewise defined so as to exhibit a quadratic function in a finer quantization interval, and an exponential function in a coarser quantization interval.